What some Tab Grouping commands do?!

[rey]

Can somebody please explain to me what some Tab Grouping features do?

So here i created a group, right clicked it and there is a toggle Save Group = what it actually does? I see it adds launch icon to tab bar - so it's actually bookmark = then why call it Save?
At the same time, if i right click on that group icon in tab bar there is UnPin command that erases icon from tab bar, BUT when i click on group in tab bar - Save Group is still toggled On... Feels like strange contradiction.

There is another menu item - Hide Group, which results in group disappearing from tab bar = so it's actually Close group = why call it Hide?

When i click group icon in bookmarks bar(created above) it launches whole group loading all tabs.(Which is inconvenient) I enabled Lazy tabs loading, but that changed nothing, whole group is still loaded at the same time. Is there a way to open a group but only one tab loaded? 
So far i found only way to open one link from group in a separate(non-grouped tab)

Initially i thought groups are usefull to say have all tabs of same domain "visually distinct", or to make "same thematic" pages be gropped for easier bookmarking, but since group is loaded at once it brakes the reason to use groups for that. So what are they for?

[S8F8ry]

The "Save" function for groups allows you to reopen the tabs within that group through the group icon in your bookmark bar after the browser restarts. You can think of it as a kind of temporary bookmark – one you can easily remove when you no longer need it.

It's called "Hide group" because this group still retains a way to restore it from the folder icon on the bookmark bar. If this group isn't already saved, it's essentially a "Close group".

The tab groups feature was designed for managing multiple tabs collectively. As such, the entire group's content functions as a single unit; it doesn't support loading just a single tab within the group individually. Google designed this feature this way from the start: Keep tabs on your tabs in Google Chrome.